Glossary

Materials Glossary

Below is a glossary of materials commonly found in NAJO jewellery.

925 sterling silver is a precious metal and one of the ‘noble’ metals. It is an alloy of silver containing 92.5% of silver and 7.5% of other metals, usually copper. Fine silver or pure silver (99.9%) is too soft to produce functional objects and is therefore alloyed with copper to give strength while still preserving the beauty of the precious metal.

Agate is a stone that comes in a wide variety of colours, both natural and dyed. It often features ‘bands’ of colour and is translucent in appearance.

Amazonite (sometimes called “Amazon Stone”)is found naturally as yellow-green or blue-green in colour, and may have fine white streaks. Because of its bright green colour when polished, Amazonite is often used as a gemstone.

Amethyst isaform of quartz which can range naturally in colour from light mauve to deep violet. The name comes from the ancient Greek meaning “intoxicated” (it was believed that the amethyst could protect one from drunkenness) It can also be heat treated to turn the stone to yellow, green and brown.

Base metal is a term used to indicate a metal that is not precious or “noble” (such as silver or gold) Base metal generally refers to metals that oxidise and corrode easily. Examples are iron, copper, nickel, lead and zinc.

Brass is an alloy of copper and zinc and because of its bright, gold like appearance, malleability and low melting point it has often been used in jewellery making.

Bronze is a metal alloy consisting mainly of copper, and usually combined with tin. Bronze usually has a more rose gold appearance than brass due to its copper content, however the metal can range from yellow to brown in colour.

Carnelian (also spelled cornelian) is a form of the mineral chalcedony. It can vary greatly in colour from pale orange to dark, reddish brown and obtains its colour from the iron content in the stone.

Chalcedony is a form of silica, composed of the minerals quartz and moganite. It comes in a range of colours, including greens, blues, pinks, yellows, browns. Chalcedony may be translucent or semi-transparent, and has a waxy lustre.

Citrine is a variety of quartz and ranges in colour from pale yellow to brown (caused by ferric {iron} impurities). Natural citrines are rare; most commercial citrines are heat treated amethyst. The name citrine comes from the Latin name for yellow “citrina”

Copper is a chemical element with a very high thermal and electrical conductivity. It has a reddish-orange colour, is soft and malleable and oxidises easily.

Coral is formed from the skeleton of marine plants. Natural red coral is prized as a gemstone and is extremely rare due to overharvesting. Most red coral used today is actually dyed white coral.

Cubic zirconia is a synthesized material and is created by treating minerals, including calcium oxide, under extremely high temperatures in a device called a skull crucible. Cubic zirconia has a very similar structure and appearance to natural diamonds. It is widely used in jewellery designs due to its low cost, durability and flawless appearance.

Enamel used by NAJO is usually ‘cold-enamel’, which is a type of epoxy resin applied to silver jewellery by hand and then warmed over a period of time to enable the enamel to set.

Freshwater pearl is formed by inserting a plastic or shell nucleus inside a mollusc. The mollusc secretes a solution and forms around the nucleus in layers (which forms the nacre) and eventually develops into a pearl. The translucent quality and sheen of the pearl nacre comes from the refraction of light through the successive layers. The thinner and more numerous the layers of nacre, the finer the lustre.

Garnet is a silicate mineral that has been used since the Bronze age as a gemstone. It is generally a darkish red colour but can also be found in orange, yellow and green. It is usually transparent.

Gamuza means “chamois” in Spanish. It is a synthetic suede cord that is used for hanging pendants around the neck. Najo supplies Gamuza in a variety of colours.

Green amethyst is also referred to as prasiolite, which is natural (purple) amethyst that has been heat treated. Most prasiolite results from a combination of heat treatment and irradiation. (See “Amethyst”)

Hematite (also spelled haematite) is the mineral form of iron oxide. It can vary in colour from black to red but is most commonly seen as a steel grey colour. Hematite was very popular in the Victorian era , particularly for intaglio engraved gems. It has been detected on the planet Mars by an infrared spectrometer.

Howlite is a whitish, porous stone and is very often dyed. It can be found in any colour but most commonly it is dyed a turquoise colour as the veins resemble those in the turquoise stone. This is often marketed as turquenite.

Lapis Lazuli or “stone of heaven” is a relatively rare semi-precious stone and has been prized for thousands of years for its intense deep blue colour. It can be found with varying amounts of calcite (white) and pyrite (yellow) content that run like veins or are spotted through the stone. Apart from jewellery, it has been used extensively in mosaics and inlays, and most splendidly in the artefacts and effigies of Ancient Egypt.

Mabe pearl is created by inserting a nucleus into a mollusc. Because the nucleus is flat the secretion from the mollusc forms over the nucleus and the mollusc shell forms the mabe’s base. The mabe, still including its nucleus, is cut out from the mollusc shell. Mabe pearls usually are grown in circular and teardrop shapes.

Marcasite Jewellery was extremely popular in the 18th century, the Victorian era and in the Art Nouveau period. It is made from faceted pyrite stones set into silver, and not, as commonly thought, with the mineral marcasite.

Mother of pearl (also known as nacre) is a protective layer produced by molluscs such as pearl oysters, abalone and freshwater mussels on the inside of their shell to help defend soft tissues against parasites and damaging debris. It has an iridescent appearance and is highly sought after for inlays in jewellery, furniture and musical instruments.

Nitrile is a synthetic rubber extruded in a tubular form. It can be used in neck pieces to hang pendants.

Onyx is a form of quartz, often with bands of colour. While pure black onyx is natural, agate is often dyed black and sold as onyx.

Peridot is one of the few gemstones that occur in only one colour, an olive green. The shade depends on how much iron is contained in the crystal structure, so the colour can vary from yellow-green to brownish green. The most valued peridot gems are a dark olive green colour.

Quartz is the most abundant single mineral on earth and makes up approximately 12% of the earth’s crust, occurring in a wide variety of igneous, sedimentary and metamorphic rock. It is usually a clear to milky white stone. It is part of a large family of semi-precious gemstones.

Resin is a two-part mixed plastic derived from coal tar and petroleum that can be coloured or used clear with objects embedded in it. Resin can easily be poured into a mould, allowing unusual shapes and multiple copies to be made.

Rutilated quartz is a popular form of quartz containing gold to reddish coloured ‘needles’ or ‘hair like’ strands of the mineral rutile. These fine gold strands appear to be trapped in the clear quartz and have been called ‘Venus Hair’ or ‘Cupid’s Darts’.

Stabilised (or reconstructed) turquoise, hematite, coral etc Stabilised, or reconstructed, these so called stones are a mixture of crushed natural stone with a strong acrylic resin that creates an inexpensive alternative to its more costly natural stone. They are often dyed to enhance the colour of the stone.

Stainless steel is a rust resistant iron-carbon alloy. Due to its hard metal state it cannot be resized or engraved.

Tourmalinated quartz is clear quartz that contains long needles or flecks of black or dark green tourmaline.

Turquoise is a blue/green opaque mineral and has been prized for thousands of years as a gem and ornamental stone owing to its extraordinarily beautiful colour. The name comes from an old French word for ‘Turkish’ as it was brought to Europe, via Turkish traders, from mines in Persia.

Production Processes

NAJO jewellery is created using a number of processes.

Hand made

NAJO’s Mexican silver jewellery is handcrafted in the workshops of Taxco, Guerrero, Mexico. Silversmiths may employ, for example, metal sheeting and dies where the metal sheet is pressed into a die (concave shape) so that it forms the shape of the die. The shapes are then hand soldered together to form jewellery.

A common technique is planishing. The jewellery piece is cut out and the surface is finely shaped and smoothed by hammering the metal against a shaped metal tool known as an anvil.

Another hand-made process is ‘drawing’ or forcing silver through a hole so it is extruded as a wire or tube, which can then be used to make rings, bangles, chain etc.

Lost wax casting

The lost wax jewellery casting process starts with a master model of the piece to be recreated. A mold is made of the master model which is injected with wax to create a wax replica of the original piece. Inside a flask, the wax replica is surrounded by plaster. The flask is placed into an oven and the wax is completely melted from the mold. A hollow void is left in its place which is then filled with molten metal. Once cooled the piece is cleaned, polished and finished.

Stamping

A process used to make light-weight jewellery. Silver sheets are stamped with dies (like cookie cutters) to produce cut-out shapes which are then assembled into jewellery. Light-weight earrings, pendants and charms are often made in this manner.

Electroforming

A very complex and labour intensive process, in which silver is electroplated onto a shape, usually made of wax. The shape is submerged into a bath and treated with a solution that forms a thin base-metal layer over the wax. It is then treated in another solution in order for a thicker silver layer to develop over the base-metal layer. When finished, the shape is warmed so the wax interior melts away from the form through a small hole, leaving the finished piece of silver.

Cold enamelling

Cold enamel is a type of epoxy resin that can be applied to metal. Once the jewellery has been hand-painted with the cold enamel, the piece is then heated so the paint and the silver bond.

Gold sheeting

A sheet of gold (NAJO usually uses 18 carat and approximately 0.3mm thick) is laminated under heat and pressure onto a sheet of sterling silver, out of which shapes are cut and incorporated into jewellery.

Oxidation

Silver can be treated with a Liver of Sulphur solution to turn it black. The silver piece can then be polished so the black finish remains only in the indentations, and throws into sharp relief the brighter, highly polished sections of the design.

Plating

Plating of metal is achieved by dipping jewellery in a solution that has an electric current running through it - this causes a thin layer of silver/gold etc to build up on the jewellery. Plating improves the appearance of the surface and increases scratch resistance. Italian and Asian silver is often silver plated to give it a bright, white appearance and to increase scratch resistance. Mexican silver is not silver plated because it is hand polished, which also gives it a bright appearance.

The plating used on Najo gold plated jewellery is usually 18 or 22 carat.

Rhodium plating is more popular in Europe and is similar to the colour of white gold. Stone-set jewellery is usually rhodium plated. Black rhodium plating gives silver a grey to black finish.

Anti-Tarnishing

Sometimes silver can be coated with an anti-tarnishing solution that will protect the piece from the oxidation or blackening that normally occurs when the metal is exposed to airborne sulphur. The anti-tarnish solution will also give the surface a brighter and glossier appearance. A large percentage of Najo jewellery is anti-tarnished.

Technical Glossary

Bale is a component which is used to attach or suspend a pendant from a chain or cord – commonly in the form of a triangular loop which can be clipped or soldered on to a ring.

Hallmark is a stamp in the metal to indicate the purity of the silver alloy that is used (925) and the identity of the company or silversmith that has made the piece. It can also indicate the date and/or location of the manufacture.

Inclusion is a mark or pattern in a stone which has been caused when a material such as another mineral or water has been trapped during the formation of the stone.

Lariat isa necklace in the form of a lasso, with one end threading through the other and hanging down the wearer’s chest.

Ring sizes NAJO stocks women’s rings in sizes LARGE, MEDIUM, SMALL (and occasionally EXTRA SMALL). These sizes correspond approximately with the british sizings of R, P, N and L and the american sizings of 9, 8, 7 and 6, respectively.

NAJO Size

USA

British

inside circumference

inside diameter

X SMALL

6

L ½

52mm

16.5mm

SMALL

7

N ½

55mm

17.5mm

MEDIUM

8

P ½

57mm

18mm

LARGE

9

R ½

60mm

19mm

Shank is the part of the ring that encircles the finger

Stone finish

Cabochon is a stone cut with a convex top and flat bottom and polished to a smooth surface.

Faceted is a stone cut with many flat, geometric ‘faces’ giving the stone a glittering appearance. Gemstones are cut with facets in order to improve their appearance by allowing them to reflect light.

Stone setting

Pavé setting uses many small gemstones that are set closely and held in place by little beads (grains) of the setting metal. The surface then looks like a continuous surface of stones, hence its name which means paved.

Bezel setting uses a metal rim that encircles the sides of a gemstone and holds it in place.

Claw setting uses pieces of metal which extend from the shank of the ring and hold the stone in place like a claw.

Channel setting is where the stone is dropped down between two rims that hold the stone in place

Gypsy (flush mount) setting is where the stone is countersunk into the metal and sits flush with the surface of the metal.

Grains are the small beads of metal on the ring surface that are pushed against the stone to hold and keep it in place.

Surface finish

Polished means a high bright, shiny surface.

Matte means a scratchy, dull finish created by abrasion or filing.

Diamond-cut means a frosty or glittery finish created by drilling silver with special, fine drills.

Beaten means hammered with tool to create an uneven surface.

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About us

Najo is an Australian Jewellery brand that has been creating sterling silver jewellery for over 30 years. Najo was first born and inspired by the inescapable spirit of Mexico and many of our pieces are still hand made by artisan silversmiths there today. We offer a range of sterling silver bracelets, earrings, necklaces and rings, as well as a Steel jewellery range. Inspired by the rich mosaic of life our jewellery offers an enduring elegance and timeless appeal.

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